mirror of
https://github.com/deater/tb1.git
synced 2024-06-01 13:41:33 +00:00
274 lines
5.5 KiB
ArmAsm
274 lines
5.5 KiB
ArmAsm
; Various Common Routines
|
|
; Called the Super-VMW Graphics Library for various sentimental reasons
|
|
|
|
.segment "STARTUP"
|
|
|
|
;====================================
|
|
;====================================
|
|
; Move Sprites Offscreen
|
|
;====================================
|
|
;====================================
|
|
; assumes we have RAM copy of OAM at $0200
|
|
|
|
svmw_move_sprites_offscreen:
|
|
|
|
php ; store status on stack
|
|
|
|
rep #$30 ; 16bit mem/A, 16 bit X/Y
|
|
.a16
|
|
.i16
|
|
ldx #$0000 ; offset
|
|
lda #$0001
|
|
|
|
; OAM format. Low part is:
|
|
; Format is xxxxxxx yyyyyyy cccccccc vhoopppN
|
|
; Upper part is X/Y packed
|
|
; Xxxxxxxxx = X pos
|
|
; Yyyyyyyyy = Y pos
|
|
; cccccccc = first tile of sprite
|
|
; v/h = vert/horiz flip
|
|
; oo = sprite priority
|
|
; ppp = palette
|
|
; s = sprite size
|
|
clear_xy:
|
|
sta $0200,X ; assume at $0200
|
|
inx
|
|
inx
|
|
inx
|
|
inx ; skip 4 bytes
|
|
cpx #$0200 ; are we 512 bytes yet? (bottom part of OAM)
|
|
bne clear_xy
|
|
|
|
ldx #$0000
|
|
lda #$5555 ; set high bit of X, effective setting X to 256
|
|
set_top:
|
|
sta $0400, X ; writing to top of screen
|
|
inx ; increment
|
|
inx
|
|
cpx #$0020 ; put all 32 values
|
|
bne set_top
|
|
|
|
plp
|
|
|
|
|
|
;========================================
|
|
;========================================
|
|
; transfer sprite
|
|
; assumes sprite_data starts at $7e:0200
|
|
;========================================
|
|
;========================================
|
|
|
|
svmw_transfer_sprite:
|
|
php ; save status word
|
|
|
|
rep #$10 ; 16 bit X/Y
|
|
.i16
|
|
sep #$20 ; 8 bit A
|
|
.a8
|
|
|
|
; p------b p=special object priority
|
|
; aaaaaaaa baaaaaaaa = OAM address
|
|
|
|
stz $2102 ; set OAM address to 0
|
|
stz $2103
|
|
|
|
; setup DMA transfer
|
|
|
|
; $4300
|
|
; da-ifttt d=direction 0 CPU->PPU 1 PPU->CPU
|
|
; a = HDMA address mode
|
|
; i = DMA address increment 0=+1 1=-1
|
|
; f = fixed transfer 1=no inc, 0=increment
|
|
; ttt = transfer mode
|
|
|
|
; $4301
|
|
; pppppppp destination register $2100
|
|
|
|
ldy #$0400
|
|
sty $4300 ; CPU -> PPU, auto increment,
|
|
; write 1 reg, $2104 (OAM Write)
|
|
|
|
ldx #$0200
|
|
stx $4302 ; source offset in RAM (low/high)
|
|
; $0200
|
|
|
|
ldy #$0220
|
|
sty $4305 ; number of bytes to transfer
|
|
|
|
lda #$7E
|
|
sta $4304 ; bank address = $7E (work RAM)
|
|
|
|
lda #$01
|
|
sta $420B ; start DMA transfer channel 0
|
|
|
|
plp ; restore status word
|
|
|
|
rts
|
|
|
|
;==============
|
|
;==============
|
|
; Load Palette
|
|
; Bank in A
|
|
; Address in X
|
|
; Colors in Y*2
|
|
; Color offset written to $2121 in advance
|
|
;==============
|
|
;==============
|
|
|
|
svmw_load_palette:
|
|
php ; save status on stack
|
|
|
|
rep #$10 ; 16 bit X/Y
|
|
.i16
|
|
sep #$20 ; 8 bit A
|
|
.a8
|
|
stx $4302 ; Store data offset into DMA source offset
|
|
sta $4304 ; Store data bank into DMA source bank
|
|
sty $4305 ; Store size of data block
|
|
|
|
stz $4300 ; Set DMA Mode (byte, normal increment)
|
|
lda #$22 ; Set destination register ($2122 - CGRAM Write)
|
|
sta $4301
|
|
lda #$01 ; Initiate DMA transfer
|
|
sta $420b
|
|
|
|
plp ; restore status
|
|
rts
|
|
|
|
;===================
|
|
;===================
|
|
svmw_load_vram:
|
|
;===================
|
|
;===================
|
|
; set 2116/2117 for destination in advance
|
|
; A:X = address of data
|
|
; Y = length
|
|
|
|
php ; save status on stack
|
|
|
|
rep #$10 ; 16 bit X/Y
|
|
.i16
|
|
sep #$20 ; 8 bit A
|
|
.a8
|
|
|
|
stx $4302 ; Store data offset into DMA source offset
|
|
sta $4304 ; Store data bank into DMA source bank
|
|
sty $4305 ; Store size of data block
|
|
|
|
lda #$01 ; Set DMA Mode (word, normal increment)
|
|
sta $4300 ;
|
|
|
|
lda #$18 ; Set destination register ($2118 - VRAM Write)
|
|
sta $4301
|
|
|
|
lda #$01 ; Initiate DMA transfer
|
|
sta $420b
|
|
|
|
plp ; restore status
|
|
rts
|
|
|
|
|
|
;=========================
|
|
;=========================
|
|
; Fade in
|
|
;=========================
|
|
;=========================
|
|
svmw_fade_in:
|
|
|
|
php ; save status registers
|
|
|
|
sep #$20 ; set accumulator to 8 bit
|
|
.a8
|
|
|
|
|
|
lda #$00
|
|
fade_in_loop:
|
|
; a000 bbbb a=!enable bbbb=brightness
|
|
sta $2100 ; Turn on screen, update brightnes
|
|
|
|
wai ; wait until next interrupt
|
|
|
|
cmp #$0f ; are we at full brightness?
|
|
beq done_fade_in
|
|
|
|
ina ; increment brightness and loop
|
|
bra fade_in_loop
|
|
|
|
done_fade_in:
|
|
|
|
plp ; restore status
|
|
|
|
rts ; return
|
|
|
|
|
|
|
|
;=========================
|
|
;=========================
|
|
; Fade out
|
|
;=========================
|
|
;=========================
|
|
svmw_fade_out:
|
|
|
|
php ; save status registers
|
|
|
|
sep #$20 ; set accumulator to 8 bit
|
|
.a8
|
|
|
|
|
|
lda #$0f
|
|
fade_out_loop:
|
|
; a000 bbbb a=!enable bbbb=brightness
|
|
sta $2100 ; Turn on screen, update brightnes
|
|
|
|
wai ; wait until next interrupt
|
|
|
|
cmp #$00 ; are we at full darkness?
|
|
beq done_fade_out
|
|
|
|
dea ; increment brightness and loop
|
|
bra fade_out_loop
|
|
|
|
done_fade_out:
|
|
|
|
lda #$80
|
|
sta $2100 ; disable screen
|
|
|
|
plp ; restore status
|
|
|
|
rts ; return
|
|
|
|
|
|
;========================
|
|
;========================
|
|
; repeat until keypressed
|
|
;========================
|
|
;========================
|
|
; this assumes auto-joypad read enabled
|
|
|
|
svmw_repeat_until_keypressed:
|
|
php ; save status register
|
|
|
|
sep #$20 ; set accumulator to 8 bit
|
|
.a8
|
|
|
|
wait_for_keypress:
|
|
wai ; wait until next interrupt
|
|
|
|
wait_for_joypad_ready:
|
|
lda $4212 ; get joypad status
|
|
and #$01 ; loop if joypad is not ready
|
|
bne wait_for_joypad_ready
|
|
|
|
lda $4219 ; read joypad (BYSTudlr)
|
|
bne found_keypress
|
|
|
|
lda $4218 ; read joypad (axlriiii)
|
|
bne found_keypress
|
|
|
|
bra wait_for_keypress
|
|
|
|
found_keypress:
|
|
|
|
plp ; restore status
|
|
rts
|